package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Follow;
import com.hmdp.mapper.FollowMapper;
import com.hmdp.service.IFollowService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IUserService;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class FollowServiceImpl extends ServiceImpl<FollowMapper, Follow> implements IFollowService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private IUserService userService;

    @Override
    @Transactional
    public Result follow(Long followUserId, Boolean isFollow) {
        Long userId = UserHolder.getUser().getId();
        // 1. 判断是否关注
        if(isFollow){
            // 2. 关注，插入数据
            Follow follow = new Follow();
            follow.setUserId(userId);
            follow.setFollowUserId(followUserId);
            boolean isSuccess = save(follow);
            if (isSuccess){
                // 把关注的用户id保存到Redis的set集合 sadd user:follows:1 2 3
                stringRedisTemplate.opsForSet().add("follows:" + userId, followUserId.toString());
            }
        }else{
            // 3. 取消关注，删除数据
            boolean isSuccsss = remove(new QueryWrapper<Follow>().eq("user_id", userId).eq("follow_user_id", followUserId));
            if (isSuccsss){
                // 把取消关注的用户id从Redis的set集合移除
                stringRedisTemplate.opsForSet().remove("follows:" + userId, followUserId.toString());
            }
        }
        return  Result.ok();
    }

    @Override
    public Result isFollow(Long followUserId) {
        Long userId = UserHolder.getUser().getId();
        // 查询是否关注：select count(*) from tb_follow where user_id = ? and follow_user_id = ?
        Integer count = query().eq("user_id", userId).eq("follow_user_id", followUserId).count();
        return Result.ok(count > 0);
    }

    @Override
    public Result followCommons(Long id) {
        Long userId = UserHolder.getUser().getId();
        Set<String> intersect = stringRedisTemplate.opsForSet().intersect("follows:" + id, "follows:" + userId);
        if (intersect == null || intersect.isEmpty()){
            // 没有交集
            return Result.ok(Collections.emptyList());
        }
        // 将关注的用户id（String) 转为 Long
        List<Long> ids = intersect.stream().map(Long::valueOf).collect(Collectors.toList());
        List<UserDTO> userDTOS = userService.listByIds(ids)
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());
        // 返回用户信息UserDTO
        return Result.ok(userDTOS);
    }
}
